摘要:
The invention provides a foamed body of thermoplastic resin having a high expansion ratio, desired shape and cells of desired diameter, especially fine cells. The foamed body of thermoplastic resin is produced by filling the thermoplastic resin containing a foaming agent into a cavity 31 of a mold 2a and thereafter enlarging the cavity 31 to expand the resin. In this process, the cavity 31 is completely filled with the resin as melted and containing the foaming agent, then held in its shape as filled with the resin and enlarged to an increased final cavity width upon the average temperature filled in the cavity 31 reaching the range from the melting point of the resin to the melting point plus 30° C.
摘要:
The invention provides a foamed body of thermoplastic resin having a high expansion ratio, desired shape and cells of desired diameter, especially fine cells. The foamed body of thermoplastic resin is produced by filling the thermoplastic resin containing a foaming agent into a cavity 31 of a mold 2a and thereafter enlarging the cavity 31 to expand the resin. In this process, the cavity 31 is completely filled with the resin as melted and containing the foaming agent, then held in its shape as filled with the resin and enlarged to an increased final cavity width upon the average temperature filled in the cavity 31 reaching the range from the melting point of the resin to the melting point plus 30° C.
摘要:
An object of the invention is to provide an injection molding process for preparing thermoplastic resin molded articles and an injection molding apparatus for use in practicing this process, the process and the apparatus being adapted to supply a blowing agent, especially a nonreactive gas such as carbon dioxide or nitrogen gas, to a thermoplastic resin continuously at a relatively low pressure with good stability to incorporate the agent or gas into the resin. As shown in FIG. 3, a resin in a cylinder (2) of an injection molding machine (1) as melted by rotating a screw (3) is mixed and dissolves carbon dioxide which is supplied to the molten resin from a gas supply opening (5) formed in the screw (3). An amount of the gas-incorporating molten resin is measured out and injected into a mold cavity to obtain an expansion-molded article. To incorporate carbon dioxide into the molten resin, the gas is supplied from a gas inlet (11) formed in a rear end portion of the screw to a portion (4a) not fed with the resin and positioned between front and rear screw flights and closer to the front flight, through a gas supply channel 6 extending through the screw and via the supply opening (5).
摘要:
The invention provides a foamed body of thermoplastic resin having a high expansion ratio, desired shape and cells of desired diameter, especially fine cells. The foamed body of thermoplastic resin is produced by filling the thermoplastic resin containing a foaming agent into a cavity 31 of a mold 2a and thereafter enlarging the cavity 31 to expand the resin. In this process, the cavity 31 is completely filled with the resin as melted and containing the foaming agent, then held in its shape as filled with the resin and enlarged to an increased final cavity width upon the average temperature filled in the cavity 31 reaching the range from the melting point of the resin to the melting point plus 30° C.
摘要:
The invention provides a foamed body of thermoplastic resin having a high expansion ratio, desired shape and cells of desired diameter, especially fine cells. The foamed body of thermoplastic resin is produced by filling the thermoplastic resin containing a foaming agent into a cavity 31 of a mold 2a and thereafter enlarging the cavity 31 to expand the resin. In this process, the cavity 31 is completely filled with the resin as melted and containing the foaming agent, then held in its shape as filled with the resin and enlarged to an increased final cavity width upon the average temperature filled in the cavity 31 reaching the range from the melting point of the resin to the melting point plus 30° C.
摘要:
The invention provides a molding apparatus adapted to use a screw having an overall length permitting the use of an existing molding machine cylinder as it is, and is capable of realizing a gas impregnation step. The screw 3 for use in the gas impregnation step comprises a resin melting portion C disposed at an upstream position for rendering the resin molten, a molten resin nonfilled-up portion E integral with the downstream side of the resin melting portion C for making the resin lower than an inert gas at a gas supply opening 5 in pressure, and a gas impregnation portion D integral with the downstream side of the molten resin nonfilled-up portion E for supplying the inert gas and impregnating the molten resin with the inert gas.